Bulletin of the American Physical Society
2006 APS April Meeting
Saturday–Tuesday, April 22–25, 2006; Dallas, TX
Session W7: Cosmic Rays and Solar Physics II |
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Sponsoring Units: DAP Room: Hyatt Regency Dallas Pegasus A |
Tuesday, April 25, 2006 10:45AM - 10:57AM |
W7.00001: Upper Limit of the Diffuse Flux of UHE Neutrinos from HiRes Data Weiran Deng, Kai Martens The cosmic ray spectrum as measured by HiRes experiment suggests the existence of GZK neutrinos. We describe the HiRes neutrino simulation and present a first result from the neutrino search in the data. [Preview Abstract] |
Tuesday, April 25, 2006 10:57AM - 11:09AM |
W7.00002: An Upper Limit on the Photon Flux above $10^{19}$ eV David Barnhill The Pierre Auger Observatory is designed to investigate the highest energy cosmic rays. Of particular interest is the composition of these cosmic rays as it indicates the nature of the source. In this presentation, data from the surface detector of the Pierre Auger Observatory will be compared to monte carlo predictions based on a primary photon assumption. A prescription will be set forth in determining primary photon candidates and a resulting upper limit on the photon flux will be presented. [Preview Abstract] |
Tuesday, April 25, 2006 11:09AM - 11:21AM |
W7.00003: Stringent Constraint on Galactic Positron Production John Beacom The intense 0.511 MeV gamma-ray line emission from the Galactic Center observed by INTEGRAL requires a large annihilation rate of nonrelativistic positrons. If these positrons are injected at even mildly relativistic energies, higher-energy gamma rays will also be produced. We calculate the gamma-ray spectrum due to inflight annihilation and compare to the observed diffuse Galactic gamma-ray data. Even in a simplified but conservative treatment, we find that the positron injection energies must be $\alt$ 3 MeV, which strongly constrains models for Galactic positron production, especially dark matter annihilation. [Preview Abstract] |
Tuesday, April 25, 2006 11:21AM - 11:33AM |
W7.00004: Planck Scale Cosmic Rays Bennie Ward We argue that the final state of Hawking radiation for a very massive black hole results in a Planck size remnant which may decay into Planck scale cosmic rays. [Preview Abstract] |
Tuesday, April 25, 2006 11:33AM - 11:45AM |
W7.00005: Comparison of Electron Stochastic Acceleration Models with RHESSI Hard X-ray Observations of Solar Flares Paolo Grigis, Arnold Benz Acceleration of charged particles in a plasma by means of stochastic interactions with turbulent waves is very efficient and therefore is often invoked as the key mechanism acting in solar flare electron acceleration. We compare the photon spectra produced by electrons accelerated using the Transient Time Damping (TTD) mechanism with the detailed hard X-ray observations provided by RHESSI for footpoint and looptop sources, showing the soft-hard-soft behavior in the spectral evolution. The TTD model with a simple leaky box escape term fails to quantitatively match the observed spectral behavior, requiring too large variations in photon flux over the range of observed spectral indices. We discuss more realistic models and further modifications needed to reproduce the RHESSI observations. [Preview Abstract] |
Tuesday, April 25, 2006 11:45AM - 11:57AM |
W7.00006: Development of the FNIT detector for 2-20 MeV solar neutrons Ulisse Bravar, Paul J. Bruillard, Erwin O. Flueckiger, Alec L. MacKinnon, John R. Macri, Mark L. McConnell, Michael R. Moser, James M. Ryan The Fast Neutron Imaging Telescope (FNIT) is a newly developed neutron detector with imaging and energy measurement capabilities, sensitive to neutrons in the 2-20 MeV energy range. FNIT was conceived as a candidate instrument for the Solar Sentinels program. Its design is optimized to measure neutrons produced in solar flares from the inner heliosphere. The detection principle is based on multiple elastic neutron-proton scatterings in plastic scintillators. By measuring the scattering coordinates and determining the energy of recoil protons and time of flight of scattered neutrons, the energy spectrum and incident direction of primary neutrons can be reconstructed. We present the results of recent laboratory efforts and describe the performance of the FNIT prototype. [Preview Abstract] |
Tuesday, April 25, 2006 11:57AM - 12:09PM |
W7.00007: The Presence of the Chromosphere: Evidence for a Liquid Model of the Sun Pierre-Marie Robitaille Critical Opalescence occurs at the critical point. It is that point in the phase diagram where the transition between liquid and gas is no longer discernable. In the laboratory, critical opalescence occurs as the meniscus disappears. There is often strong scattering of light and a transparent solution becomes cloudy. In approaching the critical point gases slowly begin to gain order as they prepare to enter the condensed state. In this presentation, it will be advanced that the Chromosphere of the Sun represents matter at the critical point. As such, the Chromosphere experiences a unique combination of temperature, pressure and gravity wherein the gaseous matter in the corona is preparing to condense onto a liquid photosphere. It is consequently stated that the very existence of the Chromosphere, constitutes a powerful piece of evidence in favor of condensed models of the Sun (http://www.arxiv.org/html/astro-ph/0410075 [1]). Additional evidence for a liquid plasma model of the Sun will also be presented. [Preview Abstract] |
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